Role of the carbon source in the activation of ribonucleic acid synthesis during the germination of Neurospora crassa conidia

Abstract

Neurospora crassa wild-type conidia incubated in minimal media synthesize ribosomal RNA (rRNA), transfer RNA (tRNA), and polyadenylate-containing RNA [poly(A) + -RNA] during the first hour of germination. Likewise, spores incubated in media containing only the carbon source (sucrose-only medium) synthesize a qualitatively similar spectrum of RNA molecules. However, at this stage, a quantitative difference (decrease) in the amount of poly(A) + RNA is detected in spores incubated in sucrose-only medium. At 3 h into germination, spores incubated in a minimal medium continue to synthesize the same spectrum of RNA molecules as at 1 h. Spores incubated for 3 h in a sucrose-only medium exhibit an alteration of the polysome profile and RNA synthesis. In addition, approximately 75% of these spores do not form germ tubes. In those which do form a germ tube the germ tube never elongates beyond one cell diameter.